Oddbean new post about login | logout they both serve a purpose. I recommend both SimpleX and Briar, they both have PFS. Adoption is important for privacy and security. IMO Signal/Molly has more users and is easy to use, so it's good for day-to-day communication and normie adoption while SimpleX and Briar are currently better suited for more specialized use cases.
I use Signal when I don't care if spooks are seeing it 🤙🏼
my biggest gripe with signal is that it does not provide anonymity. i think simplex is ready for mass adoption. it is well on its way to being a matrix killer, and a signal killer. molly dev has been teasing something cool for anonymous registration for a couple of years now but still no eta afaik. but for now, the feedback i've received from users and clients is that most people still have a hard time onboarding normies (and their friends and family) to signal, much less simplex